[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-1-en-105":3,"doc-seo-571881-105":53,"doc-detail-571881-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,14,19,24,29,34,39,44,49],{"id":8,"doc_module":9,"doc_module_name":10,"category_name":11,"show_sort_weight":12,"slug":13},11,1,"Template","Presentations",90,"presentations",{"id":15,"doc_module":9,"doc_module_name":10,"category_name":16,"show_sort_weight":17,"slug":18},12,"Resumes",80,"resumes",{"id":20,"doc_module":9,"doc_module_name":10,"category_name":21,"show_sort_weight":22,"slug":23},14,"Invoices",70,"invoices",{"id":25,"doc_module":9,"doc_module_name":10,"category_name":26,"show_sort_weight":27,"slug":28},15,"Posters",60,"posters",{"id":30,"doc_module":9,"doc_module_name":10,"category_name":31,"show_sort_weight":32,"slug":33},16,"Social Media",50,"social-media",{"id":35,"doc_module":9,"doc_module_name":10,"category_name":36,"show_sort_weight":37,"slug":38},17,"Forms",40,"forms",{"id":40,"doc_module":9,"doc_module_name":10,"category_name":41,"show_sort_weight":42,"slug":43},18,"Letters",30,"letters",{"id":45,"doc_module":9,"doc_module_name":10,"category_name":46,"show_sort_weight":47,"slug":48},21,"Paper Templates",5,"papers-templates",{"id":50,"doc_module":9,"doc_module_name":10,"category_name":51,"show_sort_weight":4,"slug":52},158,"General","general-158",{"code":4,"msg":54,"data":55},"ok",{"site_id":56,"language":57,"slug":58,"title":59,"keywords":60,"description":61,"schema_data":62,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","iptcp-header-cheat-sheet-ipv4-subnetting","IP/TCP Header Cheat Sheet - IPv4 Subnetting","","IP/TCP Header Cheat Sheet provides a compact, field-by-field reference for decoding IPv4 and TCP header structures. It explains byte/block sizing, how the destination portion separates IP and TCP headers, and details key IPv4 fields such as version, IHL, TOS, packet length, identification, fragmentation flags, TTL, encoding, and header checksum. It also covers TCP header elements including ports, sequence and acknowledgement numbers, header length, flags interpretation, window size, TCP checksum, urgent pointer, options, and where payload begins. A CIDR-to-subnet-mask, address-count, and wildcard mapping table supports IPv4 subnetting.",{"@graph":63,"@context":122},[64,80,101],{"@type":65,"itemListElement":66},"BreadcrumbList",[67,71,74,77],{"item":68,"name":69,"@type":70,"position":9},"https://docshare.wps.com","Home","ListItem",{"item":72,"name":10,"@type":70,"position":73},"https://docshare.wps.com/template/",2,{"item":75,"name":11,"@type":70,"position":76},"https://docshare.wps.com/template/presentations/",3,{"item":78,"name":59,"@type":70,"position":79},"https://docshare.wps.com/template/iptcp-header-cheat-sheet-ipv4-subnetting/571881/",4,{"url":78,"name":59,"@type":81,"image":82,"author":87,"headline":59,"publisher":90,"fileFormat":93,"inLanguage":57,"description":61,"dateModified":94,"datePublished":95,"encodingFormat":93,"isAccessibleForFree":96,"interactionStatistic":97},"DigitalDocument",{"url":83,"@type":84,"width":85,"height":86},"https://docshare.wps.com/thumbnails/iptcp-header-cheat-sheet-ipv4-subnetting/571881.png","ImageObject",442,249,{"name":88,"@type":89},"\tCallum ","Person",{"url":68,"name":91,"@type":92},"DocShare","Organization","application/pdf","2026-10-21","2026-10-13",true,{"@type":98,"interactionType":99,"userInteractionCount":47},"InteractionCounter",{"@type":100},"ViewAction",{"@type":102,"mainEntity":103},"FAQPage",[104,110,114,118],{"name":105,"@type":106,"acceptedAnswer":107},"How do you determine where the IP header ends and the TCP header begins?","Question",{"text":108,"@type":109},"Everything before the destination IP address belongs to the IPv4 header, and everything after that portion is treated as the TCP header in the cheat sheet’s structure. The TCP/IPv4 boundary is shown directly in the diagram.","Answer",{"name":111,"@type":106,"acceptedAnswer":112},"What do key IPv4 fields like IHL and TTL mean?",{"text":113,"@type":109},"IHL defines the IPv4 header length in 32-bit words, so an IHL value of 5 corresponds to 20 bytes. TTL indicates the time-to-live for the packet; the example shows how a hexadecimal TTL maps to a numeric TTL value.",{"name":115,"@type":106,"acceptedAnswer":116},"How are TCP flags decoded in this cheat sheet?",{"text":117,"@type":109},"The cheat sheet explains that TCP Flags Field includes 2 hex characters (8 bits), and the bits correspond to CWR, ECN-Echo, URG, ACK, PSH, RST, SYN, and FIN. It also demonstrates how the given hex value maps to which flags are set (e.g., ACK and FIN).",{"name":119,"@type":106,"acceptedAnswer":120},"How does the CIDR table relate subnet size to subnet mask and wildcard?",{"text":121,"@type":109},"The subnetting section lists each CIDR prefix (e.g., /24) with its subnet mask, number of addresses, and wildcard value. This allows converting between prefix length and the corresponding IPv4 subnetting parameters quickly.","https://schema.org",{"og:url":78,"og:type":124,"og:title":59,"og:site_name":91,"og:description":61},"article",{"robots":126,"canonical":78},"index,follow",{"doc_id":128,"site_id":56},571881,1792338041,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":88,"user_avatar":133,"doc_module":9,"category_id":8,"category_name":11,"doc_title":59,"doc_description":61,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":47,"is_deleted":4,"is_public":9,"is_downloadable":9,"audit_status":9,"page_count":73,"language":139,"language_code":57,"site_id":56,"html_lang":57,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":61,"update_tm":143,"read_time":9},137451211410,"https://ap-avatar.wpscdn.com/avatar/2000bb0a9246f588df?x-image-process=image/resize,m_fixed,w_180,h_180&k=1786362646172706240","IP/TCP Header Cheat Sheet  \nEach Block Represents 1 byte (8 bits) and double wide blocks count as 2 bytes etc... Everything before the Dest. IP address is the IP header (Bold Text) and everything after is the TCP header (Italicized) . Produced by Chris Davis.  \n\n| 4 | 5\u003Cbr>IP vers. |IHL | 00\u003Cbr>TOS | 00 28\u003Cbr>Packet length | eb 66\u003Cbr>IPID | 40 00\u003Cbr>Flags/Fragmentation | 40\u003Cbr>TTL | 06\u003Cbr>Encoding | b4 ab\u003Cbr>Checksum |\n| --- | --- | --- | --- | --- | --- | --- | --- |\n| oa oa oa 80\u003Cbr>Src IP Address |  |  | \u003Cbr>d0 6d b5 c6\u003Cbr>Dest. IP address |  | b9 50\u003Cbr>Src Port |  | 00 50\u003Cbr>Dest. Port |\n| 6c e5 9f 79\u003Cbr>Sequence Number |  |  | 61 d8 31 a9 Acknowledgement Number |  | 50\u003Cbr>TCP/HL | 11\u003Cbr>Flags | 75 40 Window Size |\n| 9a d8\u003Cbr>Checksum |  | 00 00 Urgent Pointer | TCP Options or Start of Payload |  | Payload---> |  |  |\n\n|-----1 byte-----|----1 byte----|------------2 bytes---------|---------------------------4 bytes---------------------------|  \n1. IP version. The first four bits (1 hex) represents either ipv4 or ipv6 . IHL is the IP header length and compose the second 4 bits (1 nibble) of block 1. An IHL of 5 would mean that the IP header length is 20 bytes ( 5 x 4 ) . If the IHL is a length of 6 then the IP options field will be 4 bytes after the ip Checksum.  \n2. TOS stands for Type of service and has to do with prioritizing traffic. In this instance 00 means no prioritizing.  \n3. Packet size simply refers to the entire size of the packet so that the router know how much space in the buffer to allocate. I.e. -- \" 00 28\" in hex would be 40 bytes.  \n4. IPID-Simply the identifier for the packet so the receiving end knows how to organize the data.  \n5. Fragmentation-This field refers to how the packets are fragmented. A value of \"4\"000 is Dont Fragment. \"2 \"Must Fragment. \"8\" Reserved. \"0\" is last frag packet.  \n6. TTL-Time to live. In this case, \"40\" in hex would be a TTL of 64.  \n7. Encoding-Refers to the IP encoding of this packet. In this instance, there is a value of \"06\" which simply means TCP. 01 is ICMP. 11 is UDP. 02 is IGMP. 09 is IGRP. 2f is GRE. 32 is ESP. 33 is AH. 39 is SKIP. 58 is EIGRP. 59 OSPF. 73 for L2TP.  \n8. Checksum of the IP header to validate the header hasn't been changed.  \n9. Source IP address  \n10. Destination IP address  \n11. Source Port  \n12. Destination Port  \n13. The TCP Sequence number used by the transport layer to order data.  \n14. The Acknowledgment field is used to acknowledge receipt of data.  \n15. The TCP/HL is the TCP header length and \"50\" in hex would just be \"5\" as we ignore the 0 in this instance. So a value of \"5\" means the TCP header length is 5x4=20 bytes.  \n16. TCP Flags Field. This has 2 hex (8 bits) . Depending on the bits that are turned on, it represents either CWR, ECN-Echo, URG, ACK, PSH, RST, SYN, or FIN. This bits are aligned as follows: | C | E | U | A | P | R | S | F | In this instance, the Hex characters are \"11\" which would equate to 17 in decimal and would have the following bits in this order: | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 1 | We can deduce that the ACK, FIN flags are set.  \n17. The TCP windows size field is used to show the number of bytes that can be transferred to the dest before an ACK should be sent.  \n18. The TCP header Checksum is used to validate the integrity of the TCP header field.  \n19. Urgent pointer field is used to identify the location of urgent data within the packet. In most cases it will be 00 00.  \n20. The TCP options Field represented in the graph is 4 bytes but can actually be 0-40 bytes. This field will often not exist and depends on the TCP/HL (refer to 15) . Since the TCP header length was only 20, the TCP header ended after the urgent pointer and there is no TCP options in this example. This would start the payload if there was one. There is often not a TCP options field . Options are:  \n0 End of Options 1 No operation (pad) 2 Maximum segment size 3 Window scale 4 Selective ACK ok 8 Timestamp  \n2  \n[IP](IPV4 SUBNETTING packetlife.net)[V](","cbCaih7GRs7H8maJ","https://ap.wps.com/l/cbCaih7GRs7H8maJ","pdf",142892,"English","# IP/TCP Header Overview\n## IPv4 Header Fields\n## TCP Header Fields\n# IPv4 Subnetting Reference (CIDR Table)","[{\"question\":\"How do you determine where the IP header ends and the TCP header begins?\",\"answer\":\"Everything before the destination IP address belongs to the IPv4 header, and everything after that portion is treated as the TCP header in the cheat sheet’s structure. The TCP/IPv4 boundary is shown directly in the diagram.\"},{\"question\":\"What do key IPv4 fields like IHL and TTL mean?\",\"answer\":\"IHL defines the IPv4 header length in 32-bit words, so an IHL value of 5 corresponds to 20 bytes. TTL indicates the time-to-live for the packet; the example shows how a hexadecimal TTL maps to a numeric TTL value.\"},{\"question\":\"How are TCP flags decoded in this cheat sheet?\",\"answer\":\"The cheat sheet explains that TCP Flags Field includes 2 hex characters (8 bits), and the bits correspond to CWR, ECN-Echo, URG, ACK, PSH, RST, SYN, and FIN. It also demonstrates how the given hex value maps to which flags are set (e.g., ACK and FIN).\"},{\"question\":\"How does the CIDR table relate subnet size to subnet mask and wildcard?\",\"answer\":\"The subnetting section lists each CIDR prefix (e.g., /24) with its subnet mask, number of addresses, and wildcard value. This allows converting between prefix length and the corresponding IPv4 subnetting parameters quickly.\"}]","IP/TCP Header Cheat Sheet - IPv4 Subnetting | PDF",1791924215]